617a4fd2d2
Remember if a mixer object is open or closed. Don't call open() again if it is already open. This guarantees that the mixer plugin is always called in a consistent state, and we will be able to remove lots of checks from the implementations. To support mixers which are automatically opened even if the audio output is still closed (to set the volume before playback starts), this patch also adds the "global" flag to the mixer_plugin struct. Both ALSA and OSS set this flag, while PULSE does not.
81 lines
1.9 KiB
C
81 lines
1.9 KiB
C
/*
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* Copyright (C) 2003-2009 The Music Player Daemon Project
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* http://www.musicpd.org
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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/** \file
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*
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* This header declares the mixer_plugin class. It should not be
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* included directly; use mixer_api.h instead in mixer
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* implementations.
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*/
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#ifndef MPD_MIXER_PLUGIN_H
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#define MPD_MIXER_PLUGIN_H
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#include <stdbool.h>
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struct config_param;
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struct mixer;
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struct mixer_plugin {
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/**
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* Alocates and configures a mixer device.
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*/
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struct mixer *(*init)(const struct config_param *param);
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/**
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* Finish and free mixer data
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*/
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void (*finish)(struct mixer *data);
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/**
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* Open mixer device
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*/
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bool (*open)(struct mixer *data);
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/**
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* Close mixer device
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*/
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void (*close)(struct mixer *data);
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/**
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* Reads the current volume.
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*
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* @return the current volume (0..100 including) or -1 on
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* error
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*/
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int (*get_volume)(struct mixer *mixer);
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/**
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* Sets the volume.
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*
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* @param volume the new volume (0..100 including)
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* @return true on success
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*/
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bool (*set_volume)(struct mixer *mixer, unsigned volume);
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/**
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* If true, then the mixer is automatically opened, even if
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* its audio output is not open. If false, then the mixer is
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* disabled as long as its audio output is closed.
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*/
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bool global;
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};
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#endif
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